Figure 2.

The B cell hypothesis of rheumatoid arthritis pathogenesis - Part One. This hypothesis proposes that B-cell precursors (A) develop in the bone marrow, (B) exit to the peripheral blood, and (C) reach the subchondral region of the joint via vasculature and lymphatics. A similar
process would occur within synovial membrane (not shown). (D) An affected metacarpal (or metatarsal) head is shown with a cortical erosion (arrow)
and infiltration of the underlying bone marrow as shown in Figure 3.